Signaling system



Nov. 17, 1936. w. H, EDWARDS 2,061,227

SIGNALING SYSTEM Filed Feb. 10, 1930 Plug Paty 9 8 g-Sacket 7 Soc/ei 1 f1 INVENTOR BY WEEzZzz/alfds ATTORNEY Patented Nov. 17, 1935 UNITEDSTATES PATENT OFFICE :,mzzv sIGNALmG SYSTEM William H. Edwards, GreatNeck, N. Y., signor to American Telephone and Telegraph Company, acorporation of New York Application February 10, 1930, Serial No.427,385 7 Claims. (Cl. 177-7) This invention relates to signalingsystems. Such a system has the disadvantage that it re- Moreparticularly this invention discloses animquires a considerable amountof power wiring proved code-calling system of the type which and thewiring must be run in ilexible armored may be used forsimultaneouslyoperating sigcable or conduit in order to satisfactorily meet nalingdevices at a plurality of locations in acthe requirements-for iireprotection. Sounding 5 cordance with selected codes without requiringdevices may, of course, be designed to operate the use of power wiring.It also discloses an imfrom a low voltage supply which utilize the sameproved auxiliary signaling system for producing amount of power foroperation as the higher signals over signaling conductors in conjunctionvoltage devices. However, the use of such de- 10 with telephone calls.vices would not reduce the wiring cost because 10 A code calling systemof the type involved in the proportionally greater current would conthisinvention may nd application in large ortinue the flre hazard and alsorequire an exganlzations where certain oflicials or employees pensivewiring installation. whose business carries them to all parts of the Itwill be seen from the above explanation of plant are wanted from time totime at headthe purpose of the code calling system involved 15 quartersor on the telephone, and whose wherein this invention that it will beutilized as an abouts in the plant at any particular instant adjunct ofthe local telephone system. Thus it may be unknown; In such cases itwould inwill be desirable from the standpoints of installavolve muchloss of time if an individual search tion and maintenance to have a codecalling sysfor the person wanted were made, and this would tem whichwill operate satisfactorily and produce 20 react detrimentally upon theeiliciency of the signals distinctly even with the greatest amountorganization, of power wiring, the system being operated from Onearrangement for locating an individual a power supply comparable withthat ordinarily quickly involves the placement of a plurality ofutilized by telephone equipment. Any system electrically operated gongsor other signaling apmeeting the requirements set forth hereinabove 25paratus at various points about the plant, and will permit aconsiderable saving in the cost of causing these gongs or otherapparatus to be installation, due to the fact that the circuits operatedin accordance with a predetermined could be run in the usual type oftelephone or code when a certain person is desired. A differannunciatorwiring, such circuits being known ent code may, of course, be assignedto each as low voltage circuits. 30 person likely to be wanted. As ageneral matter This application discloses a code calling sysit will befound most convenient to have the tem meeting the requirements set forthhereincontrol apparatus for ringing the various gongs above, one of theessential features of which is located near or at the local switchboardwhich the sensitive low voltage sounding device which serves theorganization. The local switchboard requires a relatively small'amountof power and 35 operator, when infomed of the person desired, furnishessignals sufliciently loud for the purwll cause the proper code to berung. Upon pose intended. The system can, therefore, .be hearing hissignal, the individual wanted will installed with the usual type oftelephone or anstep to the nearest phone and inform the opnunciatorwiring. Another of the essential feaerator of his whereabouts and hemay, if desired, tures lies in the use of a power source of direct 40 beplaced in communication with the party wantcurrent, and this featureinvolves the provision ing him. of means for insulating the source ofdirect cur- Electrically operated code sounding devices rent from thesignaling circuit. These and other and systems are well-known in the artwhich, features of the invention will be better underupon depression ofa selected one of a plurality stood from the description hereinafterfollowing. 45 of keys or upon the insertion of a plug in a cer- InFigure 1 of my copending application, Serial tain jack, will cause asound device or a plurality No. 286,017, filed June 16, 1928, which hassince of such devices, i. e., one or more gongs or other issued asPatent No. 1,976,660, dated Octosignaling apparatus, to be operated inaccordr 9, 1934, an alternating'current of compara- 50, ance with adesired code. The code calling systively high voltage is interrupted atintervals, tems known to the art in general require constepped down involtage, rectified and then imsiderable power for the operation of thesevaripressed upon a plurality of gongs to cause their ous soundingdevices, and hence these devices operation. In the present applicationthe source are often operated from the usual 110 volt lightofalternating current is replaced by a source of ing and power supplywhere this is available., direct current which may be of equally high 55Referring now to Pig. 1 of the drawing. it will be seen that acode-calling device i is connected it may be detranstormer, or a in tn'en a maximum and then dies down and subsequently es zero. Again, duringthe process the current flows through the secondary will be betterunderstood from` winding of transformer I in one direction and thiscurrent is reduced to aero when the ilux in the core of the transformerbecomes a maximum. When the tiux decreases, the current in the sccondarywill build up in the opposite direction and will become zero when thenux is practically negligible.

rect current and, the rectifier and due to the presence of induct-0pcrates but once during the period in which the key is closed andsubsequently opened. This is so because the varying direct currentflows-in but one direction. Thus, each gong which the key is closed andopened.

In case it is desired to operate very loud songs,

or other signaling devices which may re- Thelam ance under normalconditions. The of the tungsten ilament will frequency of the 'Ihecondenser il aired. in

will be but one cycle of alternating current.

Fig. 2 shows aline 2l connected with a telephone subscriber's set, asindicated. A sensitive relay 2| and a condenser 2l are connected 75 thenbecome locked up in series relationship with the line 20. Thus, it willbe apparent that the winding of relay 2| and condenser 22 are bridgedacross the ringer and lcondenser of the telephone subscriber's set.

The armature of relay 2| will be attracted with a frequency practicallytwice that ci the alternating current used for ringing purposes. Thus,if ringing is done with 20\cycle current, the armature of relay 2| maybe attracted forty t es per second. Condenser will become charged as thearmature of relay 2| closes its front contact and it will be dischargedwhen the armature is released so as to close its back contact.

It will be apparent that no rectier is shown in the arrangementdisclosed by Fig. 2 for the reason that code signals are not beingtransmitted. Here the gongs 3 operate as long as does the ringer of thetelephone subscribers set. It will be understood that these gongs may bereplaced by ringers of the type ordinarily used in telephone subscriberssets and may be operated in the usual manner.

The winding of relay 4 is directly connected across the secondarywinding of transformer I. This relay is preferably of the slow releasetype, as shown, in order that the horn 5 or other sounding device mayremain operated throughout the interval of time that ringing current isbeing applied.

Fig. 3 discloses an arrangement in which the gongs or other Sounders maybe operated continuously and remain operated until the telephonesubscriber answers the call. When ringing current is impressed upon line20, an alternating current relay 30 will be operated by virtue of theconnection of its winding in series with line 20 and with a condenser35. The armature of relay 30 will be alternately attracted while ringingcurrent flows overline 2|) and released during the periods betweenrings. When the armature of relay 3|) closes its contact, a relay 3|will be operated, current owing from a battery 36, which may include aplurality of dry cells, through a circuit which includes the winding ofrelay 3|, a resistance 31, and the armature and contact of relay 30.Relay 3| will by virtue of the closure of the contact associated withits rst armature, the interconnected circuit including battery 36, thewinding of relay 3|, resistance 31, and the rst armature and contact ofrelay 3|. Upon the closure of the contact associated with the secondarmature of relay 3|, relay 32 will become operated, the interconnectedcircuit including battery 36, the winding of relay armature and contactof relay 32, and the second armature and contact of relay 3|. Upon theclosure of the contact associated with the second armature of relay 32,the relay 2| will become operated, current flowing from battery 36through the winding of relay 2| and the second armature and contact ofrelay 32. Immediately after relay 32 is operated, -this relay willbecome released by virtue of the opening of the contact associated withits rst armature which is in series with the winding of relay 32. Uponthe release of relay 32, relay 2| will become released by virtue of theopening of the contact associated with the second armature of relay 32.Thus, relay 2| will become operated `and released practically insynchronism with the operation 'and release of relay 32. It will beapparent that the armature of relay 2| will be attracted and released ata rather rapid rate 32, the first p even while relay 3| remains locked.,Howeven when the receiver of the telephone set is removed from itsswitch hook, the relay 34 will become operated by virtue of the ilow ofthe same current through its winding as iiows through the transmitter ofthe subscriber's set. Upon closure o! the contact associated with thearmature of relay 34, relay 3| will become released because the armatureand contact of relay 34 will be connected in shunt with the winding ofrelay 3|. Upon the release of relay 3| all of the remaining relays willbe released and will remain released.

While this invention has been disclosed in certain particularembodiments merely for the purpose of illustration, it will beunderstood that the general principles of this invention may be appliedto other and Widely varied organizations without departing from thespirit of the invention and the scope of the appended claims.

What is claimed:

1. The method of converting direct current into alternating currentwhich consists in transmitting the direct current to a condensive ele-.-ment to charge the condensive element, deriving a cycle of alternatingcurrent from the charging current, breaking the circuit of the directcurrent and connecting the condensive element to another circuit so asto discharge the condensive element, and deriving another cycle 0Ialternating current from the discharging current.

2. A current translating method which consists in transmitting directcurrent to a condenser to charge the condenser, intermittently breakingthe circuit transmitting the direct current to the condenser andconnecting the condenser to another circuit so that the condenser maybecome discharged, deriving a cycle of alternating current from eachcharge of the condenser by the direct current, deriving another cycle ofalternating current displaced 180 degrees in phase at each discharge ofthe condenser, and rectifying both halves of each alternating currentcycle.

3. A current translating method which consists in transmitting a directcurrent to charge a condensive element, breaking the circuit of thedirect current and connecting the condensive element to another circuitso as to allow the condensive element to discharge, producing two cyclesof alternating current displaced 180 degrees in phase with each otherfrom the respective charge and discharge of the condensive element, andconverting both alternating current cycles into a. slightly varyingdirect current.

4. In combination, a source of direct current, a condenser, a key havinga front contact and a back contact, means for transmitting said directcurrent to said condenser over the front contact of said key so as tocharge the condenser, means for breaking the circuit'of said directcurrent and for connecting the condenser to a circuit which includes theback contact of said key so as to allow the condenser to becomedischarged,

means for deriving a cycle of alternating current from the chargingcurrent and another cycle of alternating current displaced 180 degreesin phase with respect to the first cycle from the discharging current.

5. In combination, a source of direct current, a condenser, a devicehaving two contacts, means for transmitting said direct current to saidcondenser over one of the contacts of said device so as to charge thecondenser, means for breaking the circuit of the direct current and forconnecting the condenser to a circuit including the ing of saidtransformer for discharging laid conother of the contacts of said deviceso as to allow denser. and a full wave rectiiier connected to the thecondenser to ome discharged. means for secondary winding oi saidtransformer. deriving from the charging current a cycle oi' 7. Themethod of converting direct current into 5 alternating current and forderiving from the disalternating current with apparatus including acharging current another cycle of alternating condenser and atransformer which consiste in current, and means for converting bothalternattransmitting the direct current through the priing currentcycles into a slightly varying direct mary winding of the transformer tothe con current. denser so as to charge the condenser, recei lo 6. Thecombination of a source of direct cura complete cycle of alternatingcurrent from the rent, a key having a front contact and a back secondarywinding of the transformer. breaking contact, a condenser. atransformer, said source the circuit of the condenser and connecting theof direct current. the front contact of said key, condenser to anothercircuit. including the pri- 15 transformer being connected in seriesrelationcharge the condenser, and receiving a second tact of said keybeing connected in series relationsecondary winding of the transformer.ship with said condenser and the primary wind- WILLIAM H. EDWARDS.

